[amsat-bb] Re: The Moon is our Future / antennas

john hackett la2qaa at hotmail.com
Sat Jul 4 05:00:21 PDT 2009

Hello David,
                Principally, the same as the Fyllingsdales BMEWS steerable phased array, yes ??.

We have some info on it on OBSERVATIONS.


73 John.   <la2qaa at amsat.org>

> From: G0MRF at aol.com
> Date: Fri, 3 Jul 2009 19:21:08 -0400
> To: kd6ozh at comcast.net; amsat-bb at amsat.org
> Subject: [amsat-bb]  The Moon is our Future / antennas
> In a message dated 03/07/2009 20:46:44 GMT Standard Time,  
> kd6ozh at comcast.net writes:
> Building  a prototype that works on Earth for project like this is only a 
> few percent of  the effort required. Treating it as a radio club project 
> won't be effective as  people need to sign up for a 5-year project.
> Hi all.
> John is absolutely right in saying the complexity cannot be easily compared 
>  to a terrestrial radio project. One other thing that stands an almost zero 
>  chance of succeeding is a dish antenna that needs to point towards the 
> earth. If  NASA and the ISS have trouble with moving parts on the solar array 
> you can  imagine how much more difficult it would be on the moon.
> However, how about this.
> The problem with the higher bands is power generation / path loss / antenna 
>  gain. Any higher band like 1.2, 2.4 or 5.8G would need a high gain antenna 
>  to offset the increased path loss.
> But, instead of a conventional steerable dish....with its unreliable moving 
>  joints...How about an electrically steerable array of patches / dipoles / 
> or any  other type of antenna element.
> But how to 'point' it?
> Well. actually I think Tom Clark provided the answer for that  with his 
> proposal of a few years ago.  The principle is this: If you have 2  arrays. One 
> say on 5.6G uplink and one on 5.8G downlink, then the receiving  array can 
> electrically look in different directions for a signal from the  Earth.  
> Once the receiver has identified a signal and optimised the RX  Antenna, the 
> information on the direction of the Earth i.e. the direction of the  strongest 
> incoming signal can be used to configure the transmit array which will  
> then beam a signal back to earth with high ERP.
> Directional, high gain, and no moving parts.
> Thanks
> David  G0MRF
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

Drag n’ drop—Get easy photo sharing with Windows Live™ Photos.


More information about the AMSAT-BB mailing list